Sandwich panel structure with edge trim



Feb. 15, 1966 ELLIS 3,235,040

SANDWICH PANEL STRUCTURE WITH EDGE TRIM Filed May 5, 1963 INVENTOR. JO/2n 7T ///'6 HTTORNE Y6 United States Patent 3,235,040 SANDWICH PANEL STRUCTURE WITH EDGE TRIM John '1. Ellis, Midland, Mich, assignor to The Dow Chemical Company, Midland, Micln, a corporation of Delaware Filed May 3, 1963, Ser. No. 277,775 2 Claims. (Cl. 52-1) This invention relates to a sandwich panel structure and, more particularly, to a sandwich panel structure having an edge trim.

An object of the present invention is to provide a strong, lightweight, economical sandwich panel structure with strong and smooth edging.

An additional object of the present invention is to provide a sandwich panel structure, having the above characteristics, wherein the edge trim is snapped onto a retainer lodged between the edges of the facing sheets of the structure to fasten it in place, thus requiring no screws, bolts or rivets.

A further object of this invention is to provide a sandwich panel structure characterized by its structural simplicity, the ease of assembly of its parts, its strong and sturdy nature and its low manufacturing cost.

Other objects and advantages of this invention will be apparent from the accompanying drawings and detailed description presented hereinafter.

In the drawings:

FIG. 1 is a fragmentary plan view of a sandwich panel with an edging embodying the invention.

FIG. 2 is a fragmentary sectional view on the line 22 of FIG. 1 showing one form of the edging.

FIG. 3 is a similar view to that of FIG. 2 showing another embodiment of the present invention.

Referring now to the drawings in detail, wherein like numerals refer to like parts in the several views, the invention as illustrated in FIG. 1 and FIG. 2 shows a sandwich panel structure comprising two spaced apart parallel skin facing sheets 10, a rigid core 12 bridging between and joining the sheets but stopping short of the edge 14 of the sheets and bound by an adhesive or other means to the sheets. A retainer, indicated generally by numeral 16, extends from the edge 18 of the core 12 to the edge 14 of the sheets. The retainer 16 is a troughlike member with sides 20 and 22 and a bottom portion, together forming an elongated structure having a C- shaped cross-section, extending along and between the opposite edges of the sheets to which the sides 20 and 22 are attached, as shown, as by spot welding, soldering, brazing, an adhesive, or other appropriate means. Each of said sides has a retainer flange 26 at its edge, facing opposite to one another, and recessed from its respective adjacent sheet, as shown. An edge trim member, indicated generally by numeral 28, has a C-shaped crosssection with mating flange-like edges 30 facing one another and is adapted to snap over and embrace the retaining flanges 26 of the retainer 16. The edge trim is held in place by each of the retaining flanges of said retainer and each of the edges of the inner surfaces of the sheets. Thus, this combination of the two sheets, core, retainer, and edge trim member produces a continuous surface starting from one skin sheet, running over the outer surface of said edge trim member and concluding with the other skin sheet.

In the modification shown in FIG. 3, the structure of the retainer, indicated generally by numeral 32, differs from that shown in FIG. 2 in that each of its sides 34 and 36 has a retainer flange 33 along each edge 40 facing one another and projecting inwardly, as shown. The edge trim member of the modification shown in FIG. 3, indicated generally by numeral 42, differs from the edge "ice trim shown in FIG. 2 in that it has flange-like edges projecting away from one another. The edge trim member is thus held in place by the conjoint action of the retaining flanges of said retainer and the edge trim member. This combination of the two sheets, core, retainer and edge trim member produces a continuous surface starting from the outer surface of one sheet, running over the outer edge of one side of the retainer, past the outer edge of the edge trim member, over the outer edge of the other side of the retainer and concluding with the other sheet.

This invention is suitable for various uses including, but not limited to, table tops, desk tops, wall panels, instrument boxes, instrument housings, and truck bodies, for example.

The sheets may be constructed of any hard material such as wood, plastic and most metals. Where portability is desired, light metals such as'aluminum or magnesium and their alloys are well suited for use as skin sheet materials.

The core may be constructed of plastic foam, such as expanded polystyrene, expanded polyethylene, expanded urethane and the like, metal foam, such as cellular aluminum and the like, balsa wood, rubber foam, or any other low density, rigid material, depending on the weight and durability desired of the final product.

The edge trim member, being held in place by the conjoint action of the retaining flanges of said retainer and the edge trim member, should be constructed with the retainer in mind. Alternatively, the retainer should be constructed with the edge trim member in mind. Thus, if the retainer is constructed so that it supports those parts of the panel structure near the edges of said structure where there is no internal core support because this space is occupied by the retainer and trim, the retainer could be made from any suitable strong material.

The edge trim member can thus be made from metals, plastics, wood or any other suitable springy material. If the retainer is made from a springy material, the edge trim member should preferably be made from a rigid and strong material so that it can support the edges of the skin sheets.

Thus, the combination may be constructed so as to provide a sandwich panel which is light, strong and attractive.

If the retainer is to be spot welded to the skin sheets, then the retainer is preferably constructed from the same material as the sheets. If the retainer is to be fastened by rivets to the facing sheets, then the retainer can be constructed of any material which can support the edges of the sheets and which is capable of being fastened by rivets to the sheets.

A cover skin, erg, vinyl, plastics, leather or Wood, may be placed over the top sheet where the panel structure is to be used as a table or desk top to provide an especial appearance, durability, etc. as understood in the art.

The following example is illustrative of the invention:

Two skin sheets of approximately 0.040 inch in thickness consisting of an aluminum base alloy are bound by a rubber base adhesive to an expanded polystyrene foam core. The retainer, an elongated trough-like member having a C-shaped cross-section with two sides, each of which extends along and between the inner surfaces of each of said skin sheets and with a flange along the edge of each side facing one another, composed of extruded aluminum base alloy of similar composition to that of the skin sheets, is spot welded to each of the inner surfaces of the two skin sheets. The edge trim member having a C- shaped cross-section composed of the same aluminum alloy as that of the retainer is then snapped onto the retainer. This combination of the two skin sheets, core, retainer and edge trim member produces a lightweight sandwich panel having an edge trim with a continuous surface starting from one skin sheet, running over the outer surface of said edge trim member and concluding with the other skin sheet.

Various modifications can be made in the present invention without departing from the spirit or scope thereof, for it is to be understood that I limit myself only as defined in the appended claims.

What is claimed is:

1. A sandwich panel structure comprising a pair of spaced apart parallel skin sheets facing each other and a core bridging between and attached to the inside faces of the sheets to hold them together as a unitary structure, said core stopping short of the edges of said sheets thereby forming a recess between the inside faces of said skin sheets along the edges of said sheets, a C-shaped crosssection retainer lodged in said recess, the sides of said retainer secured to the inside surfaces of said skin sheets, the open 'portion of said retainer extending outwardly towards the outer edge of said skin sheets and an edge trim member, the ends of said edge trim member in snap engagement with the outwardly extending ends of said C-shaped retainer.

2. The sandwich panel structure as defined in claim 1 wherein the ends of said edge trim member are interfitted in snap engagement with said C-shaped retainer between the inner surface of the said surface skin near the outer edge and the outwardly extending end of said C-shaped retainer member.

References Cited by the Examiner UNITED STATES PATENTS 2,042,721 6/ 1936 Loewy 18934 2,204,818 6/1940 Obermayr 18934 2,693,922 11/1954 Ellison et 211. 2,752,672 7/1956 Tolman 18934 2,920,898 1/1960 Metcalfe et a1.

EARL M. BERGERT, Primary Examiner.

MORRIS SUSSMAN, ALEXANDER WYMAN,

Examiners. 

1. A SANDWICH PANEL STRUCTURE COMPRISING A PAIR OF SPACED APART PARALLEL SKIN SHEETS FACING EACH OTHER AND A CORE BRIDGING BETWEEN AND ATTACHED TO THE INSIDE FACES OF THE SHEETS TO HOLD THEM TOGETHER AS A UNITARY STRUCTURE, SAID CORE STOPPING SHORT OF THE EDGES OF SAID SHEETS THEREBY FORMING A RECESS BETWEEN THE INSIDE FACES OF SAID SKIN SHEETS ALONG THE EDGES OF SAID SHEETS, A C-SHAPED CROSSSECTION RETAINER LODGED IN SAID RECESS, THE SIDES OF SAID RETAINER SECURED TO THE INSIDE SURFACES OF SAID SKIN SHEETS, THE OPEN PORTION OF SAID RETAINER, EXTENDING OUTWARDLY TOWARDS THE OUTER EDGE OF SAID SKIN SHEETS AND AN EDGE TRIM MEMBER, THE ENDS OF SAID EDGE TRIM MEMBER IN SNAP ENGAGEMENT WITH THE OUTWARDLY EXTENDING ENDS OF SAID C-SHAPED RETAINER. 